SANTA CLARA -- You can almost hear a testy Pete Carroll asking Jim Harbaugh once again: "What's your deal?"
Shortly after Carroll's Seattle Seahawks traded for Percy Harvin from the Minnesota Vikings on Monday, Harbaugh's 49ers dealt for their own playmaking receiver in Anquan Boldin from the Baltimore Ravens.
Yes, that's the same Anquan Boldin who helped spark the Baltimore Ravens' Super Bowl win over the 49ers last month. His price tag: a mere sixth-round draft pick next month.
"If that becomes official, he is a great asset, he's a great player and he's another great weapon for this team," 49ers quarterback Colin Kaepernick said on ESPN's "SportsCenter."
Trades can't become official until 1 p.m. Tuesday, and that goes for the 49ers' long-prescribed deal sending quarterback Alex Smith to the Kansas City Chiefs.
Boldin's trade is contingent on his passing a physical, and he arrived in Senegal on Monday for a three-day relief effort with Oxfam America.
Free agency also commences Tuesday, and if All-Pro safety Dashon Goldson bolts for richer pastures, the 49ers might vie for one of Boldin's former Ravens teammates, Ed Reed.
Boldin comes with a $6 million salary, an amount the Ravens were so unwilling to pay that they nearly released him Friday, according to the Baltimore Sun, the outlet that first reported Boldin's pending trade.
Boldin, 32, made a 13-yard touchdown catch to give the Ravens a 7-0 lead in the Super Bowl, and he finished with six receptions for 104 yards. Boldin played his first seven seasons with NFC West-rival Arizona before being traded to Baltimore in March 2010 for three draft picks.
"Everybody saw what he was capable of this past year and what he did in the Super Bowl," Kaepernick said on ESPN. "That's just another playmaker on our team. ... We'll be happy to take him."
In an NFL Network interview, 49ers cornerback Tarell Brown also spoke highly of Boldin.
"(He is) a guy that can play inside and outside, makes big catches -- you saw what he did in the Super Bowl as well -- a physical guy, a guy who competes on every down, every play," Brown said. "So it will be a great addition to our team."
The 49ers had good reason to bolster their receiving corps and complement No. 1 target Michael Crabtree. Randy Moss is heading for free agency after his one-year stint, and Mario Manningham and Kyle Williams are coming off late-season knee injuries.
The Ravens reportedly wanted Boldin to take a $2 million pay cut. He previously balked at the notion of leaving Baltimore.
Shortly after the Super Bowl, he told NBC Sports' "Pro Football Talk" that "I'll retire a Raven, I'm not putting on any other uniform." He recently backed off that stance and told USA Today on Saturday: "If things don't work out there, I'll sit with my family, we'll talk it over, pray about it and see what God is asking me to do."
Ravens quarterback Joe Flacco expressed disappointment over losing a reliable target.
"Anquan was a great receiver for myself and for our football team," Flacco said. "It's sad to see a guy like that go. ... Anquan was a big part of this football team, a big part of this offense."
It's unknown which of the 49ers' sixth-round draft picks -- No. 12 in the round via a 2012 trade with Miami, or No. 31 in the round -- Baltimore will acquire.
Boldin has faced the 49ers more than any other opponent in his career, totaling 84 regular-season receptions for 1,053 yards and seven touchdowns. Aside from his Super Bowl touchdown, he made a 30-yard catch against Chris Culliver late in the third quarter to set up a field goal and stall a 49ers comeback.
Now Boldin will join a 49ers team that is vying for a third straight NFC West title, a task potentially made tougher by the Seahawks' addition of Harvin, who cost them three draft picks, including a first-rounder. Harbaugh owns a 3-1 record against Carroll in the NFL, and their rivalry dates back to their Stanford-USC days that included a tense postgame exchange in which Carroll wondered about Harbaugh's "deal."
The 49ers now must strengthen their most valuable asset: their defense. Depth is needed on the front line, and upgrades are being scouted for a secondary that might lose Goldson.
With nose tackles Isaac Sopoaga and Ricky Jean Francois slated to become free agents, the 49ers on Monday signed reserve Ian Williams to a two-year, $3.2 million extension. An undrafted free agent two years ago out of Notre Dame, Williams is guaranteed to earn at least $2 million, a league source confirmed.
Special teams won't be ignored in free agency. Coordinator Brad Seely's former ties with the Cleveland Browns could come into play if the 49ers pursue two of the Browns' top free agents: kicker Phil Dawson and return specialist/wide receiver Joshua Cribbs.
The 49ers are among a handful of teams who've looked into adding kicker Lawrence Tynes, formerly of the New York Giants, a league source said.
The Associated Press contributed to this report.
Born: Oct. 3, 1980
Drafted: By Arizona in 2003, second round (54th overall) out of Florida State
Traded: to Baltimore in March 2010 for third-, fourth- and fifth-round draft picks; to 49ers in March 2013 for sixth-round pick
NFL seasons: 10 (7 Arizona, 3 Baltimore)
Honors: 2003 AP Offensive Rookie of the Year; Pro Bowl 2003, '06, '08
Career vs. 49ers (includes postseason): 15 games, 90 receptions, 1,157 yards, eight TDs
Super Bowl XLVII vs. 49ers: six receptions, 104 yards, one TD
2013 postseason: four games, 22 receptions, 380 yards, three TDs
Career totals: 140 games, 772 receptions, 10,165 yards, 58 TDs
Sources: Pro-football reference, Wikipedia